Author Archives: Paul Taylor

nanoBeacon: a simple personal CW beacon

There are times when you wonder if your receiver and antenna are really working as they should. The band is dead, or empty, it’s the middle of the day, the D-Layer is sponging up every radio frequency excitation. Perhaps you can hear a few signals, but they are fleeting — and you need a steady and predictable signal source for a proper test. An RF signal generator will give you a steady carrier, but there are times when you’d prefer to have a true CW beacon to tune onto. This simple, general purpose multiband CW beacon can be run up on the frequency (or frequencies) of your choice, is powered on a 9V transistor radio battery, and can moved to attenuate to the desired signal level, for radio receiver system testing purposes.

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Scratch-built 8-band HF SSB/CW transceiver (EI9GQ) – Part 2 – Receiver completion

There’s a reason why most homebrew transceiver kits and scratch-built projects are monoband and single mode — theres a chance you’ll finish it, or at least, get it working for a while. Building a multiband HF transceiver is a big job, as any homebrewer who has attempted it will tell you. It may take years.

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20 meters, 200mW & 12,000 miles: WSPR magic!

Weak Signal Propagation Reporter is a global radio propagation monitoring and reporting network comprised of thousands of low power beacons operating on the amateur radio bands. WSPR beacons can be detected from the lowest of Medium Wave frequencies (137kHz) all the way through the HF spectrum (all the bands from 160m to 10m are popular) to the VHF bands, 50 and 144MHz. WSPR receivers decode the tiny beacon packets and upload them to a central database, at WSPRNet.org, where anyone can literally ‘see’ the propagation paths that are currently open.

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Universal VFO Controller (ATMega328 & si5351)

This board is a universal radio project controller, with an ATMega328P(U) microcontroller and lots of options. The intention was for it to become a basic building block in transceivers, receivers, transmitters, signal generators, anywhere you need either a digital controller, one to three clocks, or both. The board has headers for the common si5351 breakout board, available from Adafruit or as a .CN clone, and a 16×2 HD7044 Liquid Crystal Display using the standard 14+2 parallel data header (+2 for backlight). It brings out all of the available digital IOs (D2..D13), analogue inputs (ADC) A0..A5), as well as headers for a 12V supply, and access to the regulated 7805 5v output, access to the LCD backlight in case you wish to take control of this in software, and an FTDI-compatible USB-to-serial programming board.

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AGC for a Termination Insensitive Amplifier

For AGC controlled IF stages in receivers I have often chosen a 2 or 3 stage dual gate MOSFET strip, or a cascode arrangement with a bipolar and JFET pair.  These work well, have more than enough overall gain, and provide good AGC-controlled gain range.    I’ve also built a BiTX style transceiver (Andy G6LBQ’s design) with two Termination Insensitive Amplifier blocks. TIAs exhibit stable input and output impedance regardless of load, and work symmetrically (for receive and transmit) but are fixed gain. My BiTx receiver worked acceptably on 40m but was underpowered on 20m. Increasing the gain to make it more lively on 20m would have made it over-powered on 40m. You don’t have this problem when you have an AGC controlled IF.

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SP-2B2C: A video series on the design and construction of a Dual-Band 2 Channel QRP CW rig

My radio projects have involved a build and test effort, often spanning 3, 4 or even 6 months, culminating in one long, detailed blog post which was assembled over many months and a video that serves the dual purposes of showing and explaining the rig followed by an outing to one or more SOTA summits.

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SP-X, a pocket rig for the CW activator in a hurry!

I’ve long been interested in compact and fairly minimal SSB and CW rigs with good performance. I’m not into bells, whistles or menus. Menus are for restaurants! When hiking, walking or bouncing around summits I want to minimise things that are not absolutely necessary, things that can go wrong. Less is more when it comes to a transceiver for portable work.

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SP-9: A Compact Five band SSB/CW QRP Transceiver

‘Summit Prowler 9’ is a homebrew five band SSB/CW 5 watt transceiver designed for and tested on the summits near Melbourne Australia. This project further developed my interest and ideas on the right mix of features and design choices in a moderately compact case that any keen radio builder could reproduce in the home workshop with modest equipment. The transceiver project was completed over an 18 month period to April 2021.

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SP-8: a homebrew 28MHz SSB transceiver for a UR3LMZ 144MHz transverter

Ten meters or the 28MHz band is showing glimmers of life from sunspot cycle 25. Even so, its not an obvious choice if you want to build a portable SSB monobander and have lots of contacts. But 28MHz is the IF of choice for VHF and UHF transverters. After noticing the 6, 2 and 70cm transverters available on eBay from the workshop of UR3LMZ and the good reports from buyers, I cooked up the idea to build a 28MHz ‘transverter IF’ transceiver, to be paired with one or more VHF or UHF transverters.

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Low-band AM Tx: Chassis and finishing

This post closes off the 160 and 80m ‘Low-band’ AM transmitter series, with a description of the chassis construction, fitting the assemblies into the chassis, and front panel finishing.

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Shack of VK2KMI

Ham Radio Blog of VK2KMI

Ham Historian

A passionate amateur looks at Melbourne history

R.IT

My journey of repairing and recycling anything I put my hands on that I believe is still useful. Not just hardware, but including software with relevant content and issues in the field of Cyber Security, Vulnerability Scanning and Penetration Testing.

G4YDM Ham-Radio and SWL news

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Tj Lab

信号処理とラジオ

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W6PNG/M0SNA

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